两株侧耳属真菌对小麦秸秆化学组分及瘤胃消化率的影响

小麦秸秆木质素含量高,蛋白质等营养物质含量低,作为反刍家畜的粗饲料营养价值低,饲料化利用受到限制。通过室内小麦秸秆固态发酵试验,研究了两株侧耳属真菌Tf1（Pleurotussajor—c4u）和JG1（PleurotusCornucopiaeRoll）对小麦秸秆细胞壁化学组分的降解、瘤胃消化率和粗蛋白含量的影响。结果表明,经菌株JG1、Tf1和两菌复合发酵21d的小麦秸秆,木质素降解率分别为28．20％、30．78％和38．41％,纤维素降解率分别为19．26％、19．28％和26．65％;48h干物质瘤胃消化率分别比未发酵秸秆提高了38．62％、44．81％和55．89％,中性洗涤纤维（NDF）消化率分别提高了38．91％、49．00％和63．08％;粗蛋白含量分别比未发酵秸秆提高了58．60％、69．53％和72．22％。表明菌株JG1和Tf1在选择性降解木质素,改善瘤胃消化率,提高粗蛋白含量方面的优势,而且两菌株复合发酵具有协同作用,与单菌发酵相比,木质素降解率、瘤胃消化率和粗蛋白含量都明显提高。     

初始含水率对土壤中原油入渗的影响

为确定土壤初始含水率对原油在土壤中入渗的影响,该文利用3种土壤,根据设定不同初始含水率进行配置,开展土柱模拟试验,研究了不同初始含水率条件下原油在土壤中的入渗。试验结果表明：对于同一质地土壤,随着初始含水率的增加,原油在土壤中入渗的湿润距离和湿润推进速率均增加。原油在土壤中的入渗与土壤粉粒含量密切相关,当土壤初始含水率较低时,不同质地土壤,粉粒含量越高,原油在土壤中入渗越慢;随土壤深度增加,土壤中原油残留物的含量呈波动递减趋势;原油在土壤中入渗的湿润距离随时间的变化可用对数函数拟合,湿润推进速率与时间的关系可用Kostiakov公式拟合。     

Plant development,agronomic performance and nutritive value of forage maize depending on hybrid and marginal site conditions at high latitudes

Abstract

The objectives of this investigation were to study the effects of marginal site conditions and hybrid on plant development, agronomic performance and nutritive characteristics of forage maize (Zea mays L.) at high latitudes. Field experiments were conducted in 2008 and 2009 at three experimental sites, Kristianstad, Skara and Västerås, at increasing latitudes from 55°–60° N. Experimental design used two replicated randomized complete blocks at each site with three maize hybrids, Avenir (FAO 180), Isberi (FAO 190) and Burli (FAO 210), which were continuously assessed for plant development and harvested at various levels of maturity. The chemical composition and nutritional characteristics of harvested plant materials were analysed and hybrid responses to advancing maturity in terms of yield and nutritional qualities were evaluated. Results showed that maize hybrids required different numbers of accumulated thermal units at sites on varying latitudes to achieve developmental stages. Lowest thermal unit requirements among hybrids were observed for hybrid Avenir, and for sites it was highest for plants grown in the most northern site, Västerås. The most southern site, Kristianstad, was the only site at which all hybrids reached the dent stage (c. 450 g kg^?1 kernel DM), a recommended maturity for ensiling. The DM yields of early maturing hybrid Avenir were consistently lower than those for Isberi and Burli at all the sites. Results also revealed nutritional differences among maize hybrids at a given maturity (DM, g kg^?1), indicating that the effects of maturation should be factored into design of hybrid performance trials. This study highlights the effects of marginal site conditions and hybrids on plant development, agronomic performance and nutritional characteristics of maize hybrids at high latitudes. Further studies on marginal sites are recommended to enlighten the understanding of interaction between environmental and genetic factors on the performance of forage maize.     

利用12C6+重离子辐射和尖孢镰刀菌毒素筛选杂交兰抗茎腐病突变体

为创建抗茎腐病杂交兰资源,本研究以玉女兰类原球茎为材料,采用¹²C⁶⁺重离子辐射技术结合尖孢镰刀菌(Fusarium oxysporum)粗毒素筛选抗茎腐病突变体。结果表明,经不同剂量¹²C⁶⁺重离子辐射后,玉女兰类原球茎的死亡率差异显著,辐射剂量为50 Gy时,死亡率为54.66%;尖孢镰刀菌粗毒素对玉女兰类原球茎存活率影响显著,当粗毒素滤液浓度为80%时,玉女兰类原球茎存活率为41.98%。采用逐步筛选法对经50 Gy¹²C⁶⁺辐射后的玉女兰类原球茎进行抗茎腐病筛选,获得14个抗性系类原球茎,筛选率为4.67%;对抗性系类原球茎进行分化、生根壮苗和移栽,获得3个抗性系Z50Gt₁、Z50Gt₂和Z50Gt₃。在含80%粗毒素滤液的培养基上抗性系类原球茎的超氧化物歧化酶(SOD)和过氧化物酶(POD)的活性均高于对照,POD活性峰值比对照提高了867.67 U·g^-1·h^-1;丙二醛(MDA)含量呈现先高于对照,随着毒素胁迫时间的延长,转变为低于对照的趋势。对3个抗性系试管苗和小苗进行人工接种鉴定,结果表明,抗性系Z50Gt₂和Z50Gt₃的再生植株具有稳定的茎腐病抗性,2个抗病株系7个月大的盆栽植株病情指数分别为20.00%和19.33%,均为抗性级别。本研究结果为采用重离子辐射技术选育抗茎腐病杂交兰新品种奠定了基础。     

Effect of Selenium on Mineral Content and Nutritive Value of Melilotus officinalis L.

Plants of Melilotus officinalis L. were subjected to two different treatments: a) no selenium (Se), and b) addition of 3 mg Se L^?1 irrigation water for 45 days and samples of leaves, stems and roots were analyzed for Se, potassium (K), sodium (Na), magnesium (Mg), iron (Fe), copper (Cu), calcium (Ca), manganese (Mn) and zinc (Zn). Crude protein (CP) content, neutral detergent fiber (NDF), acid detergent fiber (ADF) and in vitro organic matter digestibility (IVOMD) were also estimated for the aerial plant tissues. In Se-treated plants Se mainly accumulated in leaf tissues, various changes in macronutrient concentrations were detected, while the micronutrient content decreased significantly. In addition, leaf CP, NDF and ADF content decreased, while IVOMD increased, possibly indicating ameliorated nutritive value. According to our findings, M. officinalis could be used either as a dietary supplement, in mixture with non-accumulator species, for livestock feed deficient in Se or for restoration of grasslands in seleniferous soils.     

不同基因型大麦离体培养花药对赤霉病菌粗毒素的反应

研究了在离体培养条件下,大麦耐、感赤霉病基因型花药对赤霉病菌粗毒素的反应。结果表明:随着赤霉病菌粗毒素预处理浓度的提高,大麦花药愈伤组织诱导率降低,愈伤组织的绿苗分化率降低。耐病基因型的愈伤组织诱导率和绿苗分化率的降低幅度均小于感病材料。说明大麦个体水平的耐、感赤霉病性与花药水平对赤霉病粗毒素反应具有一致性。     

膜生物反应器处理猪场污水研究

为探讨膜生物反应器(MBR)处理猪场污水的可行性和膜生物反应器的运行、操作条件,为膜生物反应器在处理猪场污水中的应用提供必要的基础参数,该文采用U型中空纤维膜和L式中空纤维膜生物反应器,对不同的化学需氧量(COD)及氨氮(NH⁺₄-N)进水浓度、溶解氧水平(DO)、污泥龄(SRT)进行了4种工况试验研究。结果表明,MBR作为猪场污水处理好氧段是可行的,当进水COD平均浓度为1860 mg/L,U型、L式膜平均去除率分别为84.10％,81.20％;NH⁺₄-N进水平均浓度为511 mg/L,U型、L式膜平均去除率分别为93.81％,93.61％。     

稻瘟病菌粗毒素产生的影响因素探讨

用抑制胚根生长法测定６种因素对稻瘟病菌产生毒素量的影响。结果表明，菌株间的产毒量有明显差异；最适宜的产毒条件是：选用马铃薯、蔗糖培养基，ｐＨ值在５～６，温度为３０℃，每天光暗各１２ｈ，摇动培养。     

连续夹持输送式苎麻剥麻机研制

针对苎麻剥麻劳动强度大、作业工效低等问题,该研究基于横向喂入式剥麻技术的作业特点,结合苎麻剥麻的工艺要求,设计了一种连续夹持输送式苎麻剥麻机。通过对剥麻装置、夹持输送装置和换端夹持装置等关键部件的结构设计和理论分析,确定影响剥麻质量的关键因素及作业参数范围。以剥麻间隙、滚筒转速和输送速度作为影响因素,建立苎麻剥麻的鲜茎出麻率和原麻含杂率的数学模型,结合Box-Behnken试验方案进行多目标优化试验,寻求装置作业参数对苎麻剥麻的影响规律及最优参数组合。试验结果表明：滚筒转速、剥麻间隙和输送速度对鲜茎出麻率和原麻含杂率均具有极显著影响。通过多目标参数优化分析,确定最优作业参数组合：剥麻间隙4.0 mm、滚筒转速330 r/min和输送速度0.36 m/s。基于优化参数进行苎麻剥麻的生产验证试验,结果显示：鲜茎出麻率5.04%、原麻含杂率1.18%,各指标与模型预测值的相对误差均小于5%,验证了预测模型的准确性;整机生产效率142 kg/h,达到设计指标要求;苎麻纤维的含胶率22.85%,束纤维断裂强度4.56 CN/dtex,达到《苎麻》国家标准二等苎麻纤维等别。     

哈茨木霉和黑曲霉粗酶液预处理改善秸秆产甲烷性能

为提高玉米秸秆甲烷产率,该文研究了酶对玉米秸秆预处理后厌氧发酵的指标性质和对微生物的冲击。研究发现,哈茨木霉粗酶液(酶T)和黑曲霉粗酶液(酶A)预处理后,发酵体系中初始挥发性脂肪酸(volatile fatty acid,VFA)显著增加,主要体现在乙酸的积累。发酵1 d后,酶T处理组和酶A处理组的碱度/VFA比值及可溶性化学需氧量/VFA(s COD/VFA)比值较CK组显著增加,该变化主要体现在VFA的大量减少。发酵20 d,酶T处理组和酶A处理组的累积产甲烷量分别比CK组提高了7.79%和10.06%。厌氧发酵24 h,酶T处理组中9个属的细菌丰度显著高于CK组,其中Clostridium,vadin BC27,Ruminofilibacter与纤维素的降解有关。发酵系统中古菌主要为Methanosaeta,Bathyarchaeota,Methanosarcina,Methanobacterium等。预处理影响了发酵系统中微生物的菌群结构,对改善发酵条件具有重要的调节作用。该研究为木质纤维素的沼气转化提供参考。